Author(s): Yingzheng Zhou; Dawei Guan; Liang Cheng
Linked Author(s):
Keywords: Enzyme-induced carbonate precipitation; Scour mitigation; Erodibility improvement; Soybean urease; Sand reinforcement
Abstract: Enzyme-induced carbonate precipitation (EICP) is a new developing method in the engineering of soil reinforcement. In this paper, the erosional behaviour of EICP-treated sand was investigated to explore its potential applications in scour mitigation and erodibility improvement. The urease enzymes were extracted from soybeans by low-energy coarse filtration. Granular sand columns treated with 10 U/mL of urease and 1 M of cementation solution, together with non-treated specimens, were tested in a closed flume system. The flume can generate surface-parallel flow with different shear stress for examining scour behaviour. The evolution of scouring resistance of specimens over curing time was obtained through erosion rate tests. The carbonate content and microstructure of the treated sand columns were examined. The results indicated that the carbonate content of specimens increased as a function of curing time until the cementation solution was totally converted. Enhancing the scouring resistance of specimens through EICP was confirmed, for which higher carbonate content promotes sediment incipient velocity and critical shear stress. Low erosion rates of strongly cemented sand were observed for those cured for more than 12 hours. With the increase of the specimen cementation strength, the erosion mode of the specimen changed from the surface particle eroding to the agglomerate detachment. Additionally, the microstructure analysis showed that the effectiveness of EICP for scour control was also dominated by calcium carbonate crystal features besides carbonate content.
Year: 2023